Contact mass for preparing halogenosilanes and process therefor



May 27, 1969 H. F. ZOCK 3,446,829

CONTACT MASS FOR PREPARING HALOGENOSILANES AND PROCESS THEREFOR Filed Jan. 24, 1966 Sheet of 4 fl- C0/7I/6/JV'0/7 INVENTOR.

HENDRIK FRITS ZOCK 5X 14% VZM his A TTORNEYS.

May 27, 1969 H. F. ZOCK CONTACT MASS FOR PREPARING HALOGENO SILANES AND PROCES S THEREFOR Sheet of 4 Filed Jan. 24, 1966 /'4 2'5 fa 4'4 w 07- can ear/0n 0 0 W? 7 w Mg ,M n 4 0 U fl P m p 0 A00 am 0 n. w on. o a o U 6 5 A A fl 4 0 0 r 5 m w A! May 27, 1969 ZOCK 7 3,446,829

CONTACT MASS FOR PREPARING HALOGENOSILANES AND PROCESS THEREFOR Filed Jan. 24, 1966 Sheet -Z of 4 /a 2' 1'0 m M 5a 7& Q; 4 .fx- 60/7 1 6/1570 70 i o \im 0 o O A El g A A 0 Q A D g 200 A k A 0 at 3 75 19 0 6 w: 0: 513-117 a at 11% 540% f b I I I I I I I I g w 24 JW 40 50 m g Jz- 600149715700 /0 J4 cam erx/an //V W? N TOR HENDRlK FRITS ZOCK Is ATTORNEYS,

May 27, 1969 H. F. ZOCK 3,446,329

CONTACT MASS FOR PREPARING HALOGENOSILANES AND PROCESS THEREFOR Filed Jan. 24. 1966 Sheet 4 /'0 0'0 10 4'0 0'0 0 0'0 75 f CO/VVCJ/J/OU E /Z /00- fM/can 60/71 6/"0/0/7 Z 00/? 00 g 0/0/00: 00

INVENTORS.

ATTORNEYS.

HENDRIK FRI 5 200K 1, his

3,446,829 CONTACT MASS FOR PREPARING HALOGENO- SILANES AND PROCESS THEREFOR Hendrik Frits Zock, Vlaardingen, Netherlands, assignor to Lever Brothers Company, New York, N.Y., a corporation of Maine Filed Jan. 24, 1966, Ser. No. 522,698 Claims priority, application Great Britain, Jan. 27, 1965, 3,718/65 Int. Cl. C07f 7/02 US. Cl. 260448.2 18 Claims ABSTRACT OF THE DISCLOSURE This specification is concerned with a contact mass containing silicon, a copper or silver catalyst and a cadmium promoter. This specification is also concerned with the use of this contact mass for the preparation of halogenosilanes.

RX Si 2 R2SiXz (Rochow synthesis) Dimethyldichlorosilane, diethyldichlorosilane, methylphenylchlorosilane and diphenyldichlorosilane are compounds of particular commercial importance.

A disadvantage of this process is that the yields of diorganodihalogenosilanes RgSlXg tend to be low, especially at high conversion rates of silicon, byproducts being formed in substantial proportions. Among these by-products may be found: organotrihalogenosilane RSiX triorganoha'logenosilane R SiX and organodihalogenosilane RHSiX less desired are tetrahalogenosilane SiX diorganohalogenosilane R HSiX and trihalogenosilane l-l-SiX It is believed that several of these by-products form under the influence of the spent contact mass, in particular of the free metallic copper, the content of which in the contact mass, calculated on a percentage basis, is continually increasing as the reaction progresses.

Furthermore under the influence of the spent contact mass, cracking occurs by which tarry products are formed. These tarry products cause a serious decrease in the activity of the contact mass and final-1y the reaction stops at a relatively low silicon conversion rate.

Various means have therefore been suggested to avoid this cracking action under the influence of copper. Thus it has been suggested to employ a discharge Worm in a tube reactor which discharges the consumed material and replaces it continuously with fresh contact material. Besides, the suggestion has been made to add a promoter to the contact mass which results in a decreased tendency towards cracking of the spent catalyst and consequently leads to increased yields of diorganodihalogenosilanes. Various promoters have been suggested, especially zinc and aluminum; however, none of these promoters 1301i entirely satisfactorily.

It has now been found that diorganodihalogeno-silanes can be obtained in improved yield by passing the halide over a silicon and catalyst (e.g., copper and silver) containing contact mass in which an amount of cadmium is United States Patent 3,446,829 Patented May 27, 1969 present. The cadmium may be introduced into the contact mass in elementary form or in the form of a cadmium containing compound, as, e.g., its halides, oxides and the like.

Accordingly the present invention provides a process for the preparation of organ-ohalogenosilaues in which an organohalide is reacted at an elevated temperature with a contact mass containing silicon, a metal catalyst and, as a promoter, cadmium.

This invention also provides an improved contact mass for use in the production of organohalogenosil-anes in which the relative quantities of silicon, copper and cadmium calculated as parts by Weight of the pure metal are within the following ratios: Cu:Si between 1:150 and 9:11, preferably between 1:100 and 1:10; CdzCu between 1:100 and 3:5, preferably between 6:100 gand 3:8.

For commercial purposes those contact masses are preferred which are relatively poor in copper and cadmium as far as this is compatible with high selectivity, high reactivity together with high conversion rates.

The manner in which the silicon, the catalyst (copper) and promoter (cadmium) are introduced into the contact mass is not critical. Thus these substances may be present in the contact mass in the form of a mixture of powders of the individual components, or the promoter and the catalyst may be alloyed when possible, powdered and thereafter mixed with the silicon, preferably in the form of a finely-divided powder to give a substantially homogeneousmixture. The processes of mixing and powdering can advantageously be combined by subjecting a solution containing copper ions and cadmium ions to electrolysis which may directly yield a finely divided powder. In a preferred embodiment of the invention the contact mass is stabilized, for example by heating prior to reaction, which improves especially the initial selectivity. Stabilizing of the contact mass can be carried out at temperatures between 250 and 450 C., preferably between 320 and 400 C. For satisfactory stabilizing the contact mass should preferably be heated for 2 to 40 hours. In order to shorten the stabilization period it may be advantageous to prepare an intimate mixture of a cadmium compound and a copper compound prior to stabilization, e.g., by fusion of the copper and cadmium elements or their compounds.

Cadmium as a promoter produces one or more of the following advantages:

(1) It increases the rate of reaction.

(2) It increases the selectivity for the formation of R SiX (3) It leads :to a more complete consumption of silicon in the contact mass.

(4) At high conversion rates of silicon a high selectivity and rate of reaction is retained.

(5) P-reheating of the contact mass with cadmium improves its immediate selectivity and rate of reaction.

(6) The reaction proceeds more smoothly.

The process can be applied for the preparation of dialkyldihalogenosilanes with alkyl groups containing 1 to 3 carbon atoms using, for example, methyl chloride, methyl bromide, ethyl chloride, ethyl bromide, propyl chloride or vinyl chloride as starting material. The invention further provides methods for the preparation of diaryldihalogenosilanes using, for example, phenyl bromide, phenyl chloride or naphthyl chloride as starting material.

Silanes containing ditferent organic radicals such as methylphenyldichlorosilane and methylvinyldichlorosilane are conveniently prepared by using a mixture of different organohalides such as phenyl chloride and methyl chloride or methyl chloride and vinyl chloride as a starting material.

3 The temperature at lWhlCh the reaction is suitably carried out varies for alkyl halides between 150 to 480 C., preferably 240 to 380 C., and for aryl halides between 250 to 600 C., preferably 330 to 500 C. The upper limit of the temperature ranges in which the reaction 4 RHSiX R HSiX and HSiX by means of gas liquid chromatography.

As the contact mass was easily oxidized and the principal products of the reaction hydrolysable, the reaction conditions were so chosen that no substantial amounts of may be carried out is, however, also influenced by the water and/or oxygen were present. For example, the temperature at which the organo halide commences to hydrocarbon halide used contained less than 100 ppm. decompose thermally. of water and/ or oxygen.

The reaction can be carried out at pressures between The purity of the silicon starting material was about 0.1 and 20 kg./cm. In the case of reaction with methyl 1O 99%. The main impurities were iron, aluminum, calcium chloride the preferred partial pressure is 4-10 kg./cm. and magnesium. It consisted of fractions of the following because in this pressure range methyl chloride has a particle sizes: 50 to 75 microns (11.7%), 75 to 105 boiling point between about and 50 C. microns (36.9%), 105 to 150 microns (41.4%) and 150 The process of the present invention may be carried to 210 microns (10.0%). By grinding, the iron content out by conducting the halide over and through a bed of the silicon had increased to about 2.0%. The iron conconsisting of the contact mass maintained at the reaction t t f th ili powder was redu ed in a fluidized bed temperature. Another way is to preheat the vapour to to about 0.2% by means of a magnet. Before use the he d sir d temp ratu before contacting with t silicon was always kept for at least 24 hours in a drying tact mass. Once started, the reaction proceeds exothermioven at about 1 80" C. In general however, it is not cally. For efiicient removal of the reaction heat developed necessary to e ili on of a urity of 99% or above as a it is advisable to carry out the reaction in a fluidized bed; starting t i l, Th it; o d ibl to use f however the reaction may also be carried out in a fixedsilicon containing up to 15% iron as a starting material. bed reactor. If the formation Of RHSiX2 and HSiX iS Only dry and white cuprous chloride with a particle, d ired this may e achieved y introducing a mixture size of 2 to 5 microns was used. It was used in powdered of a hydrogen and an alkyl ha de HX and RX o the mixtures with silicon (and cadmium) after the cuprous reactor chamber. chloride had been passed through a 75 micron sieve in Embodiments of the invention will now be described order to break-up clustered articles. with reference to the following examples and the accom- Th d i hlo ide a if necessary, freed from P y drawings 1 to Comprising graphs water by melting and drying, preferably in the presence illustrating the walks of the Various experiments of gaseous hydrogen chloride and after cooling powdered scribed in the examples. Percentages refer to percentage in a, mortar, Finally, it was passed through a 75 micron by weight. sieve. In 'view of the treatment the cadmium chloride used In these g g g reaction Was carried out in the was considerably coarser than the cuprous chloride. apparatus descri e cow.

The reactor used consisted of a vertical, cylindrical EXAMPLE 1 glass tube closed at the lower end and equipped with a The contact mass consisted of 120 g. silicon, 18 g. heater. It was provided with a vibrator and several thercuprous chloride and 1 g. cadmium chloride (90.7% Si, mocouples connected with a temperature recorder, an 8.8% Cu and 0.5% Cd). The weight ratio cadmium: outlet tube for the gaseous reaction products and an copper was 5.3:100. inlet tube for the vaporized organic monohalide which The contact mass was prepared by heating for 1.1 hour passes through a sintered glass filter plate, the tube having at 325 to 350 C. and for 1.2 hours at 350 to 385 C. a funnel-shaped end at a short distance above the bot- The results are given in Table I.

TABLE I Test period 1 2 a 4 5 6 7 8 9 10 11 12 13 14 15 16 17 Hours aiterstart 0.47 0.82 1.15 1.63 2.80 3.55 4.00 4.42 5.003.42 7.17 8.20 8.67 9.17 9.75 10.5 11.81 Temperature,C 340 318 316 318 325 330 330 330 330 326 327 328 329 329 333 838 338 Produetion,g.silanelhr 10.4 128 9.2 5.3 8.2 12.2 19.9 20.8 16.2 18.7 16.3 13.5 11.5 12.0 11.8 13.1 12.4 Composition RzSiXa, percent by weight 78.8 86.5 79.5 79.0 79.5 82.2 84.0 86.0 82.2 77.9 77.9 75.2 77.2 76.3 75.9 80.5 Quantityofsiinthebed (9.) 118 1 116.1 114.1 110.1 106.2 102.1 97.2 94.6 89.9 Rate of conversion, g. OH Cl/kg.

51 r so 100 so 40 100 160 170 130 160 140 120 100 110 110 120 120 si si nt 0.4 1.1 2.1 2.7 3.8 5.6 7.1 8.8 10.5 12.0 13.9 16.2 18.0 19.1 20.2 21.8 24.1

tom. In this way the powdered contact mass on the After the 8th test period the reactor was cooled to room sintered glass plate could be fluidized by means of the temperature. The interruption between the 8th and 9th halide vapour streaming through the filter plate, the 60 s P d ste for u svibrator rendering the fiuidization more uniform. The The results are illustrated graphically in FIGURES 1 inlet tube was connected with the source of organic monoand halide via a drying device and a rotameter. The outlet Durmg f expenment was observed that the tube was connected via an electrically heated cyclone R3S1X:RS1X3 WaS a g than nPrma1 that there was (serving to remove dust particles) to a Vigreux column, ahmmpprary mcrerils? m sehi'ctmty of RzslXz and Parallel the top of which was kept at a temperature equal to the t erewlth the reactivity was Increased boiling point of the hydrocarbon halide. Condensing EXAMP E 2 Silanes were allowed to drop into a coneijting Vessel: f The contact mass consisted of 120 g. silicon, 18 g. cucontents of which could be kept on the 'bOll by an electric prous chloride and 4 g. cadmium chloride (89 4% Si,

heating device. Hydrocarbon halide escaping from the top of the column was led into a trap in which it was condensed, collected and measured by volume. The silane mixture thus obtained was weighed and investigated for its content on the various silanes R SiX RSiX R SiX,

8.7% Cu and 1.9% Cd). The weight ratio cadmiumzcopper was 21:100.

The contact mass was prepared by heating for 2.5 hours at 350 C.

The results are given in Table II.

TABLE II Test period 1 2 3 4 5 6 7 8 9 10 11 12 13 14 Hours after start 0. 87 1. 87 2. 62 3. 22 3. 79 4. 37 4. 97 5. 77 6. 47 7. 29 8. 17 9. 07 9. 87 10. 9 Temperature, C 330 325 325 331 331 330 331 334 335 338 335 334 338 337 Production, g. silanes/h 8. 6 l6. 5 19. 1 22. 8 22. 7 16. 6 15. 6 13. 4 13. 5 13. 7 13. 7 12. 8 15. 2 17. 1 Composition RzSiXz, percent by weight 64. 0 77. 2 85. 8 83. 9 83. 5 77. 7 74. 2 73. 6 73. 2 75. 4 76. 0 78. 1 77. 8 80. 8 RSlXg, percent by wt 15. 4 11. 3 6. 0 3. U 7. 6 11. 6 13. 5 14. 6 14. 4 13. 3 12. 5 10. 8 11. 3 8. 5 RgSiX, percent by wt 1. 20. 6 11. 5 8. 2 8. 0 8. 9 10. 7 12. 3 11. 7 12. 1 11. 3 11. 5 11. 1 10. 9 10. 7 Quantity of Si in the bed (g.) 117. 7 111. 7 105. 8 101. 3 96. 9 92. l 86.9 Rate Of conversion g. CHgCl/kg. Si/hr 60 110 130 160 170 130 120 110 110 110 120 110 140 160 Si conversion, percent 0.6 2. 8 5. 7 8.2 10. 7 12. 7 14. 4 16. 3 18. 2 20.1 22. 3 24. 5 26. 7 29. 4 Test period 15 16 17 18 19 20 21 22 23 24 25 26 27 Hours after start 11. 9 12. 9 13- 9 1 9 15. 9 16. 9 17. 9 l8. 9 19. 9 20. 9 21. 9 22. 9 23. 9 Temperature, C 338 338 3 339 339 338 341 339 338 338 341 330 346 Production, g. silanes/hr 20.2 22.3 2 1 2 21. 0 19. 9 18.9 17. 6 l5. 0 14. 1 13. 6 9. 3 12. 7 Composition R SiX2, percent by Wt. 81. 2 86. 8 87. 8 89. 8 91. 3 91. 9 91. 9 92. O 92. 9 91. 8 92. 0 90. 5 91. 2 RSiXg, percent by wt 9. 3 5. 9 2 6. O 5. 1 4.3 4. 2 4. 7 3. 6 4.8 4. 5 4. 5 4.9 RaSiX, percent by Wt 9. 5 6. 9 5. 5 4. 2 3. 6 3. 5 3. 4 3. l 2. 9 2. 8 2. 8 3. 4 2. 8 Quantity of Si in the bed (g.) 79. 7 70. 0 60. 6 51. 5 43. 1 37. 8 33. 0 Rate of conversion, g. OHgCl/kg. Si/hr 200 240 270 270 270 280 290 290 270 270 280 210 300 Si conversion, percent 32. 7 36. 7 0. 9 4 48. 8 53. 0 56. 5 59. 9 63. 6 65. 5 68. 1 70. 2 72. 2

The total yield of silanes in this test was 476 g.

The general shape of the graphs of the results of the preceding example were obtained again but in a stronger degree (see FIGURE 3). After an initial decrease in selectivity to 73.2% R SiX at 18.2% Si conversion (see FIGURE 5) this increased again and parallel therewith the reactivity. This initial decrease in selectivity could have been minimized by stabilization of the contact mass prior to reaction as appears from Example 3. At a conversion of 53% it even amounted to 92% R SiX FIG- URE 4 shows the percentages of RSiX and R SiX in the reaction product.

EXAMPLE 3 EXAMPLE 4 The contact mass consisted of 120 g. silicon, 12 g. cuprous chloride and 8 g. cadmium chloride (90.4% Si,

The contact mass consisted of 120 g. silicon, 12 g. 5.9% Cu and 37% The Welght ratio cadmiumicop" cuprous chloride and 4 g. cadmium chloride (92.1% Si, P Was 16125- 6.0% Cu and 1.9% Cd). The weight ratio cadmiumzcop- The Contact mass Was P p by heatlng for h urs per was 8:25. at 350 C. and for 0.8 hour at 400 to 420 C., subse- The contact mass was prepared by heating for 0.5 40 quen ly 112 10 o m temperature and 18 hours after hour at 365 C., 0.5 hour at 365 to 385 C. and 1.5 t at rea tlng With CH3C1. hours at 385 to 400 C. The results are set out in Table IV.

TABLE IV Test period 1 2 3 4 5 6 7 8 9 15 Hours after start 0.5 1.0 1.5 2.0 2.5 3.0 4.0 5.0 6.0 1L8 Temperature,0. 332 328 330 330 330 330 332 332 331 350 Production, g. silan 2.24 7.62 8.48 7. 7.24 6. 98 7.27 7.00 5. 9 95 Composition RzSlX2,D8TC9I1tbYW 54.8 58.9 61.1 59.9 60.0 61.8 61.4 62.5 67.9 0.0 Quantity of Si in the bed (g.) 118.4 7.0 115.3 113. 3 110.4 101 3 Rate of conversion, g. CHgOl/kg. Si/h 17 57 64 58 55 54 57 55 47 35 Si coversion, percent 0. 1 0.6 1.3 2. 0 2. 7 3. 4 4.4 5. 7 6.8 14 5 The results are set out in Table III.

TABLE III Test period 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 1 Hours after start 0.5 1.13 1.76 2.51 3.26 4.01 4.76 5.51 6.26 7.3 8.3 9.3 10.3 11.3 12,3 Temperature, o 325 328 328 333 334 335 334 335 335 335 336 335 335 333 332 332 Production, g. silanes/h 10.5 16.4 17.2 17.6 17.6 18.8 22.6 20.1 22.4 25.6 29.1 27.0 29.1 21.3 22.0 2 Composition rt sixr, percent by wt 60.5 76.4 77.8 79.7 77.5 79.0 81.5 80.6 83.0 90.0 91.0 91.4 91.3 92.7 92.8 92.7 RSiX percent by wt 13.7 11.0 10.5 9.5 10.8 9.7 8.5 8.4 7.6 4.8 4.7 4.7 4.2 3.5 3.5 Rrsix, percent by wt 18.8 12.6 11.7 10.8 11.7 11.3 10.0 11.0 0.4 5.2 4.0 3.5 3.9 3.1 3.2 3.2 Quantity oi si in the bed (g.) 118.2 113.9 108.1 101.8 93.8 84.2 72.1 61.9 Rate of conversion, g. CHQCl/kg. Si/hr 70 120 160 220 270 270 320 250 280 390 si conversion, percent 0.5 1.9 4.1 6.5 9.0 11.5 14.3 17.3 21.0 24.1 29.1 34.3 39.3 44.0 47.9 52, Test period 17 1s 19 20 21 22 23 24 25 26 27 2s 29 3o 31 Hours after start 14.3 15.3 16.3 17.3 18.3 19.3 20.3 21.3 22.3 23.3 24.3 25.3 26.3 27.3 Temperature, c 328 331 335 330 328 332 327 337 340 340 320 325 338 340 342 Production, g.silancs/hr 19.2 17.3 18.4 17.3 12.5 12.4 7.9 10.7 18.6 12.2 8.2 5.5 5.4 5.8 6. 0 Composition R2SiX1,peI'Cent by \vt 93.2 93.3 93.7 93.3 93.6 93.2 91.8 91.8 88.8 90.8 89.7 89.2 87.1 85.3 85.9 RSiX percent by wt 3. 7 3. 6 3.2 3.3 3.3 3.4 4. 0 3.5 5. 5 4. 7 5. 1 4. 6 5. 6 6. 8 6, 6 RaSiX,percent by 2.8 2.6 2.7 3.0 2.5 2.9 3.3 3.5 4.4 3.5 4.2 4.5 5.8 6.1 6.3 Quantity of Si in thefibed 51.5 43.6 36.6 31.6 26.6 21.0 18.1 15. Rate of conversion, g. CH Cl/kg. S1/hr 290 290 330 340 270 290 210 310 550 410 310 220 230 270 300 Si conversion, percent 56.7 60.0 63.3 66.5 69.8 71.5 73.4 75.0 77.6 80.6 82.3 83.7 84.8 85.7 86 6 9 EXAMPLE 7 The contact mass consisted of 60 g. silicon, 10 g. cuprous chloride and 3 g. cadmium chloride (87.8% Si, 9.5% Cu and 2.7% Cd). The weight ratio cadmium: copper was 28.4: 100.

The contact mass was prepared by heating at 350- 420 C. for 2.0 hours. The experiment was carried out in a fixed bed at 435-445 C., while passing gaseous phenyl chloride over the contact mass with the aid of nitrogen.

For a period of 31 hours, 20 g. phenyl chloride/hr. was passed through. More than 20% of the phenylchloride was converted into phenyltrichlorosilane, biphenyland diphenyldichlorosilane. The composition of the product as appears from gas/liquid chromatography was: 78% diphenyldichlorosilane, 17% phenyltrichlorosilane and biphenyl. The weight ratio RSiCl :R SiCl was consequently 22:100.

In a similar experiment under analogous conditions without cadmium the conversion was very low the weight ratio RSiCl :R SiC1 being 1 1.

I claim:

1. A process for the preparation of lower alkyl or aryl halogenosilanes by reacting a lower alkyl or aryl halide at an elevated temperature with a contact mass containing silicon, a copper or silver catalyst and a promoter in which cadmium is used as a promoter for the production of diorganodihalogenosilanes in increased yield.

2. A process as claimed in claim 1 in which the contact mass contains silicon, copper and cadmium within the weight ratios CuzSi between 1:150 and 9:11 and CdzCu between 1:100 and 3 :5.

3. A process as claimed in claim 2 in which the contact mass is prepared by adding to the silicon a powdered fused mixture of cuprous halide and cadmium halide followed by a heat treatment at a temperature between 250 and 450 C. for 2 to 40 hours prior to the reaction with the lower alkyl or aryl halide.

4. A process as claimed in claim 1 in which the contact mass contains silicon, copper and cadmium within the weight ratios CuzSi between 1:100 and 1:10 and CdzCu between 6: 100 and 3:8.

5. A process as claimed in claim 4 in which the contact mass is prepared by adding to the silicon a powdered fused mixture of cuprous halide and cadmium halide followed by a heat treatment at a temperature between 320 and 400 C. for 2 to 10 hours prior to the reaction with the lower alkyl or aryl halide.

6. A process according to claim 1 in which the lower alkyl or aryl halide is a C -C alkyl chloride or bromide.

7. A process as claimed in claim 3 in which the contact mass is stabilized by heating it to a temperature between 320 and 400 C. for 2 to 10 hours prior to the reaction with the lower alkyl or aryl halide.

8. A process as claimed in claim 1 in which the reaction is carried out at temperatures between and 600 C.

9. A process as claimed in claim 8 in which the lower alkyl or aryl halide is an alkyl halide and the reaction with the contact mass is carried out at temperatures between 150 and 480 C.

10. A process as claimed in claim 9 in which the temperatures are between 240 and 380 C.

11. A process as claimed in claim 10 in which the lower alkyl or aryl halide is methyl chloride.

12. A process as claimed in claim 8 in which the lower alkyl or aryl halide is an arylhalide and the reaction with the contact mass is carried out at temperatures between 250 and 600 C.

13. A process as claimed in claim 12 in which the temperatures are between 330 and 500 C.

14. A process as claimed in claim 13 in which the lower alkyl or aryl halide is phenyl chloride.

15. A process as claimed in claim 9 in which the pressure during the reaction is between 0.1 and 20 kg./cm.

16. A process as claimed in claim 12 in which the pressure during the reaction is between 0.1 and 20 kg./cm.

17. A contact mass for use in the production of lower alkyl or aryl halogenosilanes in which the relative quantities of silicon copper and cadmium calculated as parts by weight of pure metal are within the following ratios:

Cu:Si between 1:150 and 9:11 CdzCu between 1:100 and 3:5

18. A contact mass as claimed in claim 17 in which the ratios are: CuzSi between 1:100 and 1:10 CdzSi between 6:100 and 3:8.

References Cited UNITED STATES PATENTS 3,155,698 11/1964 Nitzsche et al. 260448.2

TOBIAS E. LEVOW, Primary Examiner. J. P. PODGORSKI, Assistant Examiner.

US. Cl. X.R. 252-441, 475

" UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION Patent No. T5, +6,829 Dated May 27, 1969 Inventor) Hendrik; Frits ZocK It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

1 Columns 5-4, Table 1', column 7, "82.2" should be --82.8-; Columns 5-6, Table IV is out 01 sequence; Columns 56, Table IV, column 9, "67.9" should be --67.0--; Columns 7-8, Table v, column 5, "89.9" should be 89.8--;5Column 8, line 31, "8W5" should be -'-83- 5-; Columns 7-8, Table VI, in the heading "(r)" (three occurrences) should be -r--; Columns (-8, Table VII, column 12, "21.7" should be --ll.7--.

SIGNED AND SEALED MAR 2 4-1970 (SEAL) Attest:

Edward M. Fletcher, Jr.

WILLIAM E. S BUY 0 Atlesting Office.- 0 BER, JR

Commissioner of Patents 

